Aeroplane bomb fuse



Dec. 22, 1931. E. W 0. UTTER AEROPLANE BOMB uss Filed Jan. 31, 1929 A TTON/YE Y-s.

Patented Dec. 22, 1931 STATES ERNST WILI-IELM OTTO UTTER, 0F HELSINKI, SUOMI-FINLAND AEROPLANE BOMB FUSE Application filed January 31, 1929, Serial No. 336,468, and in Suomi-Finland February 21, 1928.

It is known that the exploding mechanisms for aeroplane bombs have been more or less defective. The safety device of the bomb has especially been unsatisfactory and the fuse of the bomb has often been faulty so that in cases where the axial rotation of the falling bomb has for some reason stopped this has effected a relocking of the exploding mechanism thus resulting in the failure of the bomb to explode when striking an obstacle. The exploding mechanism according to the present invention is freed from these defects.

The invention provides a construction of the moving elements of thesafety device in the nose body of the'bomb arranged in such a way that the bomb is positively secured for transportation but when the safety device once is released it cannot be automatically or unintentionally locked again.

The accompanying drawings illustrate one way of carrying out the invention into practice.

Fig. 1 shows the nose body of the bomb with fuse and auxiliary devices in longitudinal section.

Figs. 2 and 3 are detail views illustrating respectively a threaded plug with a moving pin for attachment to the nose, and a hammer with safety screw.

1 is the nose body of the bomb which is furnished with two securing plungers 2 of any usual and well known construction, the plungers acting in the conventional way when the bomb is dropped and rotates around its longitudinal axis. The hammer 3 is thicker at the active end and is furnished with a hole 4, into the known way' in which hole the endsof the securing plungers lit. The other end 5 of the hammer 3 is cylindrical also but smaller in diameter than the active end and guides the hammer spring 6, said last named end of the hammer being provided with a threaded hole 7. Between the end and point of the nose there is clearance what beyond the point of the hammer when the detonator and the hammer are secured against operation.

The detonator 9 is made in the shape of a shot gun cartridge with a percussion cap 10 in the heel 9a, and includes a ferrule 11 with a hole for the fuse 12,. which is pressed against the ferrule 11 by means of a lock nut 13. The detonator is filled with the initial exploder 14 composed of tetryl or'some other suitable explosive, and is loose in the tube 15, which is threaded in the nose body at 16. 17 is a plate tube open at the end against the nose body and provided at said endwith a flange 17a. l Vhen the bomb is filled with explosive the platetube 17 is first inserted and the bottom disc 18 with two spanner holes 18a is screwed on to such an extent as not to prevent the nose body 1 from being turned home afterwards. In the centre of the disc 18 there is a hole big enough to permit passage therethrough of the tube 15. The tube 17 thus constitutes a suitable nest inthe explosive for the accommodation of thetube .15, The helical spring 19 presses the detonator against the tube 15. The use of the aeroplane bomb may be either for instantaneous action of the fuse or with time lag action of the fuse.

Instantaneous action of the fuse The tip of the nose is furnished with a centrally drilled plug 20 having a pin 21, which has a limited axial motion. One end of the pin is loosely fitted in the hole 22 of the nose extending up to the hammer heel when the plug 20 is turned home, and at the other end is provided with a knob 23. Through the hole 24 passes a metal wire so that the knob 23 must receive an impact powerful enough to cut the wire before the pin can reach the hammer. V hen the bomb is dropped the twisted shape of the bomb wings will set the bomb into rotation thus releasing the securing plungers 2 by their centrifugal force and releasing the hammer. hen the plungers have moved far enough the detonator retainer 8 drops into the empty space 25 thus preventing the plungers entering the hole 4 and relocking the hammer 3. The spring 19 presses the detonator against the heel 9a and thereby prevents the detonator from dropping down on the point of the hammer. YVhen the bomb strikes a hard obstacle, as for in-' stance a pavement, the thrust is instantaneously transmitted from the pin 21 to the hammer thus effecting the QXPlOSlOIl. I

The fuse has time lag pressing the spring 6, and the detonator 9 will also drop and compress the spring 19.

hen the bomb has stopped, the springs 6 and 19 will kick the hammer and the detonator back and when the motion of the detonator is completed the point of the hammer will strike the percussion cap 1966 thus effecting the explosion. These additional motions of the fuse mechanism require some time in their completion so that the bomb has penetrated deeper into the obstacle before the explosion takes place.

When stored or transported the detonator 9 is removed from the bomb and the pieces 20, 21 and 23 are kept in the tube 15 and a screw 26 is inserted through the hole 22, the end of the screw being threaded to correspond to the thread 7 in the hammer. By means of said screw 26 it is possible to pull the hammer slightly downward'so as to keep the plungers 2 positively in place by friction thus making an accidental release of the hammer impossible.

Patent claims: 7 r 1. Exploding mechanism' for aircraft bombs comprising an axially movable hammer provided with a threaded recess in its outer end, adetonating charge, a per- 'cussion cap therefor, means for locking said hammer against operation and adapted to be operated by centrifugal force developed in the descent of the bomb to release said hammer, and ascrewthreaded pin arranged to be screwed into the threaded recess of said hammer for forcing it into engagement with said locking means to lock the latter against operation.

'2. Exploding mechanism for aircraft bombs comprising a nose body provided with an axial bore, a percussion cap in registry with said bore, a hammer consisting of an active head and a stem of relatively reduced diameter movably mounted in said bore, a helical spring surrounding the stem of said hammer adapted to be compressed by its inertia upon impact of the bomb with a target and to be expanded subsequently as said bomb is retarded by said impact to force said hammer against said percussion cap to effect a retarded explosion, and a firing pin adapted to be removably connected with said nose body and projecting beyond the end thereof for forcing said hammer against said percussion cap to effect an instantaneous explosion upon impact with a target.

3. Exploding mechanism for air craft bombs as set forth in claim 2 in which the hammer is provided with a transverse hole into which radially movable pins normally project to lock said hammer in its inoperative position, said pins being operated by centrifugal force developed by rotation of the bomb in the descent thereof to release said hammer, and a sleeve loosely mounted on said hammer and adapted, upon the movement of sa1d pins to releasing positions, to

drop between said pins and the hammer to prevent relocking of the latter in case rotation ofthe bomb ceases during its descent.

'4. Explosion mechanism for air craft bombs asset forth in claim 2 in which a 'd'etonator charge is axially movable in a detonator tube projecting from said nose body, and retained in said tube by means of a spring having its one end bearing against said nose body;

5; Explosion mechanism for air craft .bombs comprising a nose body provided with an axial bore, a detonator tube mounted on said body inre'gistry with said bore, a detonator charge movably mounted in said detonator tube, a hammer movably mounted in said bore for exploding said detonator charge, means for releasably locking said hammer in its inoperative position, and a sleeve for pre venting relocking of said hammer subsequently to its release and for preventing said "detonator charge from striking against said hammer when the latter is locked in its inoperative position. 7

I 6. The combination of an aircraft bomb,

, thenose of which is provided with a threaded recess, and exploding mechanism comprising an axially movable hammer,a detonating charge, a percussion cap, a firing pin removably mounted in the bomb and provided with acorresponding threaded recess, said firing pm PIOJGCtlIlg outwardly beyond the end of said bomb and adapted to transmit the initial impact of said bomb against the target to said hammer whereby the latter is driven against said percussion cap to explode the detonating charge coincidentally With said impact, and a solid knob arranged to be interchangeably threaded into either of said recesses.

In witness whereof I have hereunto set my hand. ERNST WILHELM OTTO UTTER. 

